Controlling relay



Nov. 20, 1945. PR TON 2,389,458

CONTROLLING RELAY Original Filed March 27, 1942 INVENTOR JOHN E..PRE5TON ATTORN EY Patented Nov. 20, 1945 UNITED STATES PAIL-INT.

CONTROLLING.- RELAY:

J chin E. Preston, Northport, NtYfl, asignor-tm'lhe American Laundry Machinery 60mm, Nar wood, Ohio, a corporation ot'Ohio Original. application Mai-ch27; 1342,.-

.No. 436,465.-. Dividedljand this application June 5; 1944, SrialNo. 538347 1 01m. (01. zen-'21).-

This inventionrelates totimedelay relays of the general form shown, described and. claimed: in .my prior application forsequence timerv and.

measuring control, Serial No, 436,4 65, filed March 27, 1.942," ofwhich this application is a division- In. said .iprior application, the time delay relay,-

varied by causing or producing variation .inithee rate changeof the operating: conditions inthe gridlcircuit during thenormal delayperiod.

V 'lhemachine beingcontrolled, such as ZtfOld! in: machine, performs. its operation upon the.

workwhile the work. is moving: at a substantially uniform rate, but any.- variation in=the.rate-:ofwork .travel resultsdn loss of accuate registry -between the operating device and the works at the moment or operation upon the work,.ca1-ising;said operation to be performed at thewrongaplace.

One. objectof the invention, therefore, is to provideimproved means. for compensatingefor:

variation in .thespeed of travel of .the workrtoin sure accurate. anduniform results.

Another object is toprovide a .controllingytime delay. relay of the character. described, sensitive tocontrol. by variations in the operating: conditions. of. the controlling circuit, and. including means operated .by or in accordance with therate ottraveloflthe work, or. the speed of operation of the-work moving. .means, for supplying to the con-- 34 functions as the time delay relay device, astwill" trol. circuita potential whichcompensates for. speedivariation. and therefore-insures uniform results.

StilLanother object isto provide atimedelay trol by. variations in. grid potential andincluding.

means-ion. supplementing the normal control-ling:

variation by a further variation dependent upon; or in step with variations in .thevrate. of work trawehall for the purpose described.

objectsot the inventionin part are. and .inpart will appear morein. detail hereinafter.

, lathe drawing, the :single: view showmwhich il dl-IPHCBEG' of Fig; 2. of the. drawings; of said. priorapplicatlon, isa diagram illustrating the invention. applied to a folding machine- Insaidiolding machine, the .contror devices are so constructed .anctarransedthat each ofa series towels, ,sheets or the like; and ltraveling "in" snca cession along a definite path; is folded ata definitepointpr place, proportional to .its length; suchast at the one-lialf or mid pointi at theone thir'd" point, .or: the one-quarterpoint, oratlany "other point,- always independently of variation in. the actual total article length.

In the machinesh'own, the. articles to 'b'e'ioided are advanced from. right to leftion'the upper run of "an endless. belt or conveyor l 0;.andasanarticl thus advances its leadingend edge-first, interrupts the electrical contact between 'a conducting plate II and a, first trip device I, and. thenrbetween said plate and a second trip device 2; with" effects to be later described. As.the trailing' end edge' passes-the same trips contactbetween'the plate andjsaid trips is restored, as will bereadily understood.

Beyond the second 'trip"2"tlie'article'passes the bite or opening. between rotatingifolding'rollelz, l3; opposite which isa folding blade'll'adapted trough-I61 Blade I4isactuatedbvsohinoid H; the operation of which is controlled by theelec tronic time delay relay; system now'jto. b'e'de= scribed;

86 Said relaysystem, in th'eiorm shown; includes- 45. partly.

three. standard three-element, separate heater; grid controlled A. (ii-electron discharge valvesrA,

B, C,'.two.oi.which, Aiand B. serve as triggers .for"

controlling .the operation of'the third, C} which ppe Tubes B? respectively. cooperate withtripsi I.

and'Itoenerzize or. deenergiz'erelay, coilsv l8; l1, tube ..A and its relay. being selected for. detailed. relay ofthe character described, sensitive to con-- 4o description. because the.-two sets. are eeneralh alike, so that detaileddescriptionot-both not necessary.

The-filament I9- or .tube .A. energized. from. secondary 20 ottransiormer T the wiring being.

broken. away, to. the dia'.-. gram. Grid 2| of tubeeAis. normally. biasedlby. resistor -.22 .to permit-.thepassage oi-..plate.current from cathode 23 to plate :24; Undersuch normal bias, plate current--fiows-.-through a circuitassfol 50 lows V Fromrpoint 2.5-- in thesecondarv S ot transiormerJI. bytwaye! conductors-26, 21, cathodeto:

piste. ct -tube "A; conductenlfl; rehydi duetorsjl; .32, toathe secondary-5.0: transiormerr oftartlclemvaryinem-lenzth suchwaswanapkins, T; When'relay l8:iaenergiaed-citsearnistureeu is in contact with plate II.-

moves from position b to position a, but this operation takes place only when the grid receives normal bias. Ordinarily such ordinary bias is disturbed and the tube is overbiased, with armature 34 in position b, as long as contact trip I When the trip. I" contacts plate. tary bias is imposed on grid 2I by a circuit as follows:

From point 25 of secondary S by way of con- II'a supplemenductors 25, 21, cathode to grid of tube A, resistor 22, conductor 35, trip contact I plate II, and con-' ductor 35 to voltage divider 31: across the secondcurrent in tube A whenever finger I is in contact with plate I I.

In similar manner trip finger 2, when in contact with plate II, imposes a supplementary bias on the grid of. tube B, likewise blocking the flow of plate, current th'erethrough'and deenergizing relay' H, the armature of which always is inpositionb when finger 2 contacts plate I I.

Tubes A and B therefore serve asjriggers'in the respective functioning of coils I8, H, which are therefore sensitiveto the passage of articles between plate II and trips I and 2.

Measurement of the article to determine its actual length, and its positioning at the time of fold, are accomplished or controlled by the third or relay tube or electron discharge device C, as will now appear.

The operation of tube C, as a relay, is controlled by variation of the operating conditions in the controlling grid circuit, such as by variation'of the grid potential, and more specifically, in the form shown, by control of the charging and discharging of capacitance or condenser 39, under I control ofcoils-IB, I1.

.Condenser 39 is'charged by means of the rectilied half cycle of grid current of tube 0. It is being charged only when trip finger 2 touches plate II'so as to block tube B, deenergize relay I1 and'place armature 40 in position b. Under those conditions, charging current originating in the voltage divider 31 across secondary 38 flows through'acircuit as follows:

From point 25 by conductors 26, cathode to grid of tube C, conductor 44 to capacitance 39, through'conductors 45' and 95 to generator 92, then by conductor 96, armature 40 in position b and conductor 41 back to volt'age'divider'fl;

The purpose of generator 92 and the manner of discharging'ofcapacitance 39 will be described hereinafter;

As long as capacitance 39 is under charge; its p'otential'is superimposed on the normal bias of tube C, in which the flow of plate current is there* fore blocked, so that the armature 48 lies in position b. The circuit 55, 54 to coil I5 is open and the folding blade is held retracted.

Whenever condenser 39 has d scharged sufficiently to reduce the potentialof the grid circuit of tube C to its critical operating'value the tube C serves as a relay and passes plate current through a circuit as follows: a

' From point 25 on secondaryS, by way of cnductors 26, 4|, cathode to plate of tube 6, conductor 49, coil 50 and conductor 32 back to secondary S. Coil 50 being thus energized, arma-- ture48 moves to position a, and thereupon current flows from the source L1 by conductor 54-to' solenoid l and by conductor 55 to Law Solenoid; I5 thereby is energized, and, in the specific form of machine shown for purposes of illustration, ad-

vances and produces a folding operation on the article now in proper position before it.

Discharge of condenser 39 is initiated by engagement of the leading edge of the moving article first with trip I and then with trip 2. Engagement with both is necessary. t 7

Engagement [with trip I opens the biasing circuit through conductor 35 to the grid of valve A,

w in which plate current flow is therefore established, causing armature 34 to move to position 'a. Likewise, engagement of trip 2 causes the v .flowof plate current in valve B, causing its armature 40 to move to position a. Results are as follows:

Movement of armature 40 away from position opens the charging circuit for condenser 39 begfore described.

Movement of the two armatures to position a establishes a discharging circuit for condenser 39 as follows:

From condenser 39 by wires 45, to generator 92, then,by wire 96, armature 40 in a position,

"/wire56, resistor 51, resistor 58, armature 34in a position, and wire 60 back to condenser 39. s

The two resistors 51, 5s regulate the rate of" discharge, which continues at a uniform 'rate until the trailing edge of the article passes trip I, whereupon the biasing circuit for valve A, through conductor 35 is closed. Th rise in its grid potential blocks the flow of plate current, coil I8 is deenergized and armature 34 returns to its b position.

This operation has the effect of short circuit;-

ing resistance 58, by way of wire 58a, out of the discharging circuit for condenser '39; Discharge thereof accordingly proceeds at an accelerated rate, due to the decrease in resistance; until the potential of the grid circuit has beenreduced to' the critical operating value for the valve. Thereupon the plate circuit of valve'C becomes conduc rate is entirely dependent upon the resistance the discharging current encounters in its circuit. In

the description above it was assumed that the conveyor belt causes work travel at uniform speed." It is apparent that a relationship exists between the rate of condenser discharge and the rate of work travel. Thus if the rate of work travel-is accelerated after condenser discharge has been initiated the appropriate operation point on the article will have passed beyond the foldingbladebefore the latter is operated; with error in each such operation. g

This can be corrected in several ways, for in a consequent stance by introducing a compensating variation in the resistance value of the discharging circuit;

depending upon article speed, or by varying the value .of the condenser charge, dependent onart1cle speed. I have selected the latter expedient,

the drawing showing means for opposing a com-- pensating bucking voltage to the charging volt age, with the bucking voltage directing-proportional to the rate of advance of the-article.

' It is apparent that if article 'speedincrea'se's the condenser discharge should take place in a shorter time, and consequently, in the form shown, the original condenser charge should be smaller. This means that the opposed bucking voltage should be increased if article speed increases, and it is obvious both from abstract consideration and from actual trial that there is a direct relationship between the increase in speed and the required increase in bucking voltage.

For the purpose stated I have introduced into the charging circuit for condenser 39, before described, the current generator 92, said generator being driven in any suitable manner so that its rate of rotation is proportional to the speed of article travel, such as by driving the generator directly from one of the belt driving rollers 83, by belt 94, or in any other suitable manner. This insures a direct relationship between variation in speed 01' article travel and a change in speed, and consequently in current output, of generator 92.

The generator is so connected in the circuit that its output is opposed in polarity to the charging voltage rectified in valve C. The variable voltage divider 31,-across the secondary 38 of transformer T, predetermines the basic charging rate, but the generator 92 supplies whatever compensating bucking voltage is necessary for any given conditions.

In operation generator 92 compensates not only for small speed variations such as might occur during a single cycle of operations or the folding machine, but also for any preselected wider variations chosen for convenience, within reasonable limits. For example, one kind of article may require one speed and another kind of article might be best treated at twice the former speed, etc. Whatever the reasons for variation in the speed or rate of travel of the articles, the generator 92 compensates therefor and insures proper positioning of the operation being performed upon the article in accordance with measurement thereof and proportionately to its length, as described in my said prior application. For example, if the resistances 51, 58 are of such value, both absolutely and relatively to each other, and the capacity 39 is such, that the mechanism functions to told an article at a point midway of its length, or at a point of its length, regardless of variations in its length, the arrangement described insures that the fold will actually be produced at the predetermined point, without variation or error. with the arrangement described, it is clear that the actual charge applied to the capacitance 39, during the charging operation, is dependent upon the compensating effect of generator 92, whose output is opposed to or bucks the output of the normal charging source voltage divider 31. The effect is in step with variations in speed of travel of the belts or tapes carrying the articles to be folded and which serve as the driver for the generator 92. As the speed or travel or the articles increases, the charge of capacitance 39 is reduced by the increased bucking potential supplied by generator 92. The net result is that even though the actual period or maximum time delay may vary from time to time, with variation in speed of article travel, the time delay periods for articles of difierent length always bear the same proportionate relation to each other, regardless of variations in the speed of article travel. That result is not aflected by the fact that generator 92 is also--included in the discharging circuit for capacitance 39, because said generator is then ineffective to vary the time of discharge and becomes no more than a current conductor in the discharging circuit, as will be readily understood.

What I claim is:

Apparatus of the character described, comprising means for moving an article along a path, trip means adapted to be engaged by the moving article, time delay relay means variously controlled by said trip means in accordance with variations in length of different articles traveling in said path and including a grid controlled electron discharge device and means for changing the grid potential thereof by sequential steps at JOHN E. PRESTON. 

